Quadratic Formula Equation Calculator

Math Algebra Geometry

Solves for the x, the unknown variable, in the polynomial expression of degree 2, ax2+bx+c=0. The solution is also known as the root or roots.

Note, the quadratic equation can also be solved by completing the square or factoring. However, these methods do not always provide an answer. The quadratic formula provides a solution to all quadratic equations.

The value and sign of the discriminant determines the solution type. Note, the discriminant is the expression under the square root sign.

Value of Discriminant

Type

Negative (less than zero)

Two distinct complex or imaginary solutions or roots

Equal to zero

Single real solution. This is also known as a double root solution.

Positive (greater than zero)

Two distinct real solutions

Quadratic Equation Calculator

Inputs:

a

b

c

Solution

Two solutions

x1

=

0.20416847668728

x2

=

9.7958315233127

Notes

Coefficient or Constant

Description

a

Quadratic. If a equals zero then the equation becomes a linear equation.

b

Linear

c

Constant

Note on the graph and plot

If the discriminant is negative, a line chart is not drawn.

If the discriminant is equal to zero, the line will cross the x axis once.

If the discriminant is positive, the line will cross the x axis twice.

If the solution is not imaginary, then the y axis will be crossed once.